Doctors are people too, and their advice to patients about obesity may be colored by their own views on what’s responsible for weight gain.

To determine how much doctors’ own views about the role that diet and nutrition play in a person’s weight, researchers led by associate professor Dr. Sara Bleich at the Johns Hopkins Bloomberg School of Public Health report in the journal Preventive Medicine on a survey of 500 primary care physicians who answered an online questionnaire. They queried the doctors about what they believed were the primary causes of obesity, asking them to rank the major factors responsible for their patients’ weight, including things such as over-eating, eating out at fast food restaurants, drinking too many sugared sodas, genetics, or other health conditions. The researchers also asked how often the doctors gave nutritional advice to their patients, such as teaching them how to read nutritional labels on foods at the grocery store, avoiding calorie-dense menu items when eating at restaurants or cutting down on portion sizes.

The vast majority of doctors (88%) reported that overeating is a significant driver of obesity, and they were also three times more likely to tell their patients to eat smaller portions and twice as likely to advise them not to cook with high-calorie ingredients. Sixty-two percent of physicians cited restaurant food and fast food as important contributors to obesity, and these doctors were 93% more likely to tell patients to avoid ordering high-calorie items. And the 60% who reported that sugar-sweetened beverages were a big part of the obesity problem were six times more likely to tell patients to drink less of them.

Few doctors rated genetics (19%) and metabolic defects (12%) as very important causes of obesity — which is a good sign, according to Bleich.

“Obesity [rates] have gone up so quickly that they simply cannot be explained by genetics,” she says. “What’s really driving the obesity problem are different environmental factors, so it’s encouraging to me that we’re seeing a lot of physicians acknowledging that this is actually not a genetic problem, and that there are modifiable things in a patient’s life that can promote reductions in excess body weight.”

It’s a recognition among doctors that most of the obesity epidemic, in other words, is preventable, and that curbing it is not impossible. But how doctors advise their patients to address their obesity may depend on what factor he or she believes is primarily responsible for the excess weight. That means that not all patients may be getting a comprehensive strategy for weight loss; some may be focusing on meals that they eat outside of the home, while others may be concentrating on reducing their soda intake. That’s still helpful, says Bleich, but the study shows that conversations between doctors and patients about weight could be more wide-ranging.

In fact, this isn’t the first study of Bleich’s that exposes how doctors’ own perspectives on obesity can impact the way they treat their heavier patients. In 2012, she found that doctors who are overweight or obese themselves are less likely to discuss weight issues with their overweight patients or diagnose them as obese. But she says research generally shows that obese patients are more likely to make changes to their diet if their doctors advise them to. So taken together, the results of the two studies start to shift some of the attention away from the patients and onto the primary care physicians who care for them. When it comes to addressing obesity, it may take more than simply urging people to get serious about their weight loss. Doctors, it seems, can play an important role in helping the population to shed pounds as well.